Over the years I tried several makes of panniers before finally buying some Ortlieb. I’d always considered them too expensive but if I’d bought them in the first place I don’t think I’d have needed to replace them. They’re very well made, spares are readily available, and I believe Ortlieb offer excellent after sales support. Probably the most popular make for serious cycle tourists, and I can see why.
If, like me, you need to swap them between different bikes regularly the QL2 mounting system is best, but if you usually use them on the same bike the QL1 may be better, and cheaper.